


Is that supposed to be a Time Machine?

by Bootsrcool



Series: The Harry Potter/UnderTale crossover that nobuddie asked for [6]
Category: Harry Potter - J. K. Rowling, Undertale (Video Game)
Genre: Explniations, Gen, WTF, plot progression, puns that dont make sense, talks
Language: English
Status: Completed
Published: 2016-05-14
Updated: 2016-05-26
Packaged: 2018-06-08 09:52:45
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 2,972
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6849577
Author URL: https://archiveofourown.org/users/Bootsrcool/pseuds/Bootsrcool
Summary: <blockquote class="userstuff">
              <p>Talks. Angst. Time.</p>
            </blockquote>





	1. Sans Lab - One

**Author's Note:**

> Uh, this is gonna have two parts. Two chapters. So for the hundred of you reading this, there's that.
> 
> Also, I have fallen in love with Gaster. And my own bit of theory on what he was gonna do.
> 
> Enjoy!~

Harry had been staying with the skeleton brothers for a few days now, and there hasn't been any trouble. He still got the feeling, though it was weak at the moment, that he should be moving on soon, but until the time came that he would have to, he really didn't want to leave.

Papyrus has been an excellent friend, taking Harry with it to work in the forest and they made many snow figures, had many snowball fights and played with some of the other monsters.

Sans would come with them sometimes, but he would mostly go off and do his own thing, or work in the basement. Harry had asked what he did once and Sans gave him a story about working on a machine that would do all his work for him. Harry didn't believe the story for a moment, but he felt like Sans wasn't lying either.

Right now, Harry was with Papyrus, helping him re-calibrate his puzzles when Sans ‘shortcutted,’ next to them.

“uh, pap? remember when we had that breastbone to breastbone? you didn't tell us if you told undyne or not...” Sans trailed off. Harry stiffened some, looking up at Papyrus.

“SORRY BROTHER, HUMAN HARRY,” Papyrus said, looking down as he twisted his fingers. “I FORGOT TO TELL YOU THAT I HAD TOLD HER AND THAT SHE WAS PLANNING TO VISIT LATER ON.”

Sans sighed, wiping some sweat from his skull. “it’s fine, bro. but we need to hide harry. undyne made her appearance a few minutes ago, and she thinks i'm getting ‘the human from the cage’.”

Harry flinched as Papyrus fretted, naming off places they could hide the wizard before vetoing it right away.

“WHY DON'T YOU TAKE HIM INTO YOUR WORKSHOP? UNDYNE KNOWS THAT NO ONE IS ALLOWED IN THERE!” Sans stiffened.

“no.” 

“BUT SANS-”

“It's okay, no really,” Harry said when the two brothers turned to him, about to protest. “I should start moving on anyways.” Harry tried to sound convincing. He really wanted to stay for a while longer, but he recognized the look on Sans face. The look of being uncomfortable hiding something from his friend's that could hurt them. He probably had his facial expression like that for the longest time before falling.

“n o.” Sans said again, this time more firmly. “papyrus, tell undyne whatever you want, harry will c o m e w i t h m e.”

“Bu-” 

“no time, kid.” And with that, they were appa- sorry, ‘taking a short cut’. 

With a small flare of light, Harry found himself in a dark room. “hold on,” Sans said, and Harry heard footsteps before the lights went on. Harry was speechless.

“welcome to my lab.”

Harry looked around the room, bigger than the house above them. The floor was tiled white, everything was hospital bright, there was some small machines here and there, though Harry’s attention was immediately drawn to a cloth covered lump in the corner of the room where it looked most used. Some scattered tools, empty ketchup bottles and a worktable with a few drawers.

“so, uh, rule number one is don't touch. anything. unless you want to be scattered across time and space, keep you hands to yourself. rule b, don't touch anything. the last rule is to stay close to me. hopefully, if you touch something, i can fix it before you have a bad time.”

“Bad time being scattered across time and space?” Harry guessed.

Sans smiled grimly. “got it in one.”

“Is there somewhere I can sit without that happening?” Sans looked around before walking over and bringing the chair by the covered thing over. 

“here.” Harry smiled thanking the skeleton. “nice snow skullptures by the way,” he commented offhandedly. Harry sniggered. 

“Thought you might appreciate them.” he replied. “So where is that robot you were making?”

Sans cheeks flushed blue. 

“Aaaand there’s no robot. So what are you really doing down here?”

The skeleton didn't comment, just walked over to the tarp and pulling it off. Harry stared at the portal looking machine. “Is that supposed to be a time machine?”

Sans hesitated before he nodded, then shrugged. “kinda. more like a timeline travel? like i said, it's really hard to explain, and harder to grasp.”

Harry smiled sardonically. “Try me.”

Sans shrugged. “hope you're comfortable.” Harry motioned Sans to start talking. “so, if you talked to any of the locals, you might have heard that pap and i kind of appeared one day?” When Harry nodded that, yes, he heard a few patrons at Grillby’s mention it, Sans continued. “well, we weren't ‘born’ in the way other monsters down here are. We were created by a doctor that went by the name w. d. gaster. don't think about it too hard,” Sans said when Harry got a pained look on his face. “anyways, gaster was the royal scientist before alphys. uh, you’ll probably meet her later when you move on through hotland. so gaster was the first monster tasked with figuring a way to break the barrier.”

“Toriel mentioned a barrier,” Harry interrupted. Sans looked up. “She was a woman who loved on the other side of the doors where i came out before I met you.”

“oh. i talked to her before, but we never introduced ourselves. i, uh,” Sans blushed that pretty blue color that harry was starting to like. “i would practice knock knock jokes on it when i was working and one day, someone responded. guess that must’ve been your girl.” Harry shrugged, smiling at the still embarrassed look on his friend's face. Sans shook his skull before asking, “so you don't know about the barrier?”

“Nope.” Harry responded.

“well, it goes like this. monsters used to live on the surface, but the humans decided that they didn't like the power some of us had, and lashed out at us. they started a war, monsters were dusted and seven sorcerers trapped us all below the mountain, creating a barrier by sacrificing there lives to seal us down here. anything can enter, nothing can leave. we need seven human souls to break the barrier, but a monster with a human's soul can leave and vise versa”

“That… makes a lot more sense why everyone has attempted to try and kill me or capture me. Wait, Toriel said that she has seen humans come and go before. how many humans have fallen?”

Sans thought about it for a moment before saying, “six. the king has six souls right now.” Harry groaned.

“I’m sorry.” Sans looked at Harry shocked.

“Why are you sorry?”

“I-I can't let this king take my soul. Where I’m from, there’s this, uh, guy that's trying to kill me, and takes enjoyment of hurting those I'm close with.” At Sans horrified expression, Harry rushed to explain. “It's fine, he’s been doing it since I was born so I’m used to it.”

“what!”

“Uh, nevermind. I’ll tell you more later. Finish your story, please.”

Sans searched Harry’s face for a few moments before leaning back against the wall he was standing against. “gaster tried to make a machine that could travel timelines so he would bring humans from those timelines to ours. That way, he wouldn't be taking them from this timeline, and everything would be fine.”

“It failed?” Harry questioned.

Sans nodded. “it failed. when he tested it out, he was literally scattered through time and space, forgotten by everyone.”

“Except you.”

“yeah. being in this room shielded me from losing my memories. it's like a capsule? anything in here will stay in here no matter what.” At Harry’s look, Sans sighed. “listen. this timeline business. it's not just theoretical. there was a...child, that fell down once. they, uh, were odd. very determined.”

“Didn't you mention once that determination was a physical thing?” 

Sans nodded. “yeah, and this kid had lots of it. to the point they had the power to SAVE AND RESET.”

“Like a game?” Harry asked, slightly freaked out.

“exactly like a game.” Sans confirmed, looking uncomfortable. “they, harry, i have lived through so many resets. this kid, they were scared at first. understandably, yes. they must have killed toriel or something, cause when they walked out of the ruins, she was covered in dust.” Harry had a look of horror on his face. “this kid, they looked so sad, and as far as i know, they didn't kill another being down here. they got to asgore, was forced to fight him, and then nothing. i woke up in my bed with vague memories and papyrus yelling at me to get to work.”

“That’s,” Sans shook his head. 

“that was a long time ago.” he grimaced. “for me, at least. when they came out of the ruins the next time, they were dust free, eyes full of life as they greeted me like it was the first time.”

“Was it?” Harry asked. “Did they lose their memories when they, uh, reset?”

Sans shrugged. “the kid? maybe. but i know there was something in there that knew what had happened. they went through the whole timeline without killing anything. at the end, we had all lost our memories of what happened after a flower showed up,” Sans trailed off at the look on his friend's face. “what?”

“When I first fell down,” Harry said slowly, trying to make sense of everything, “there was a talking flower there to greet me.” Harry closed his eyes, taking a deep breath and putting himself back in the moment. “I felt malice in every word he said, telling me that i could trust him. I didn't,and he tried to kill me before Toriel showed up.” 

Sans was sweating now. “shit. that's not good. uh… let me finish my story, then we’ll sort that out. while we are down here, as long as that door is closed, time passes slowly. i think the conversion is every minute down here is 30 seconds above.”

Harry agreed and Sans continued. “so, uh, what i remember is that we lost our memories after the flower showed up, the barrier was broken and we were finally free. we were standing there, watching the sunrise like it was a new start for everyone. pap was so happy, harry.” Sans squeezed his eyes shut. Harry hugged the guy close to him, patting his back and humming a random tune softly. Eventually, Sans took a shuddering breath and started talking again. 

“they reset. we were at the bottom of the mountain, and i looked over to the kid, and they just looked sad as hell and they r e s e t. i woke up in my room in snowdin, with pap yelling at me to get to work. again.” Sans let out a bitter laugh.

“What happened?”

“i ask myself that every day. when they exited the ruins, they were so different. so different. the three biggest things were that they were covered in dust; covered. they were holding a plastic knife. and the eyes were red.”


	2. Sans Lab - Two

**Notes for the Chapter:**

> Yeah... Ending is super corny but I just played Geno route so sorry. T_T

Harry flinched back so badly he almost fell out of the chair, then he did fall out, because sans startled when he flinched and they landed with Sans on top.

“Red eyes? Did they ever tell you their name? Did they have short dark hair, wearing robes? How old do you think they were?”

Sans stared at Harry as he shot off questions. “no, no they had shoulder length brown hair, striped blue and purple shirt, and i would think eleven or twelve.” Harry sighed, relieved. “harry, who was it you just described?” 

“...a bad person,” he murmured. “A very bad person.”

“the person trying to kill you?” Harry nodded.

“Yeah. D-did they ever tell you their name?”

“yes. they said they were called frisk.”

Harry frowned. “This is gonna sound really weird, but besides the, uh, murdering everything in sight,” Harry looked to Sans for confirmation on that. “was there anything else strange? were their eyes glazed, or were their movements choppy? Did it ever seem like..,”

“like they were possessed?” Sans finished with realization dawning on his face. “you think they were possessed?”

Harry shrugged. “Maybe? It's just odd that they went from, what you described, scared as hell, to happy as could be and determined to free monsters to the point of succeeding, just to reset it all.”

“i thought they could have been bored of the adventure.” Sans admitted sheepishly. 

“Wait, what about this timeline? When are they supposed to show up?”

“it differs,” Sans said. “sometimes they are in the ruins for a day, tops. other times, they could stay there for a few days to a few weeks. once they didn't show up until two months after the reset.”

“Maybe they are staying with Toriel.” Harry pondered.

“yeah, maybe,” Sans replied. “either way, it's been over a week. they should be by soon.”

“Do you want me to stick around? I could tell you if they were possessed,” the wizard offered.

“how?” Sans looked at Harry strangely.

“Uh, intuition.” Harry said weakly. At Sans unimpressed look, Harry flushed some. “Look, I know it looks really bad on me that you just spilled your guts to me, someone you've only known for a few days, and I’m keeping secrets. “I will tell you, I just,” Harry paused and searched for the right words. “I need to get my bearings straight. Um” Harry looked around for a moment. Spotting the machine, Harry motioned to it. 

“You said it didn't work, that-that,”

“gaster,” Sans supplied.

“Yeah, him. That he was scattered across time and space. What would happen if it worked now? Would he step out like nothing happened, or would someone need to go in after him?”

Sans froze, looking at Harry with his sockets wide open. “why?”

“What if I tell you I can fix it? I mean, I’m pretty sure I can. It would help me show you my, uh, secrets.”

Sans stared at Harry for a few long moments before blinking, his eye sockets empty. “this better not be a sick joke harry.”

Harry took a step back, shocked. “What? I wouldn't play a prank on you. Not like that,” Harry amended. “So what would happen?”

“...he might come out if he noticed the portal opening, but if he is truly gone, erased, then there would be nothing for it.”

“Okay. Harry stepped in front of the machine and looked around at the scattered tools. “You might want to stay close, or go stand against the wall. I don't know what will happen.”

Sans stepped forward and pressed himself against Harry’s back. Harry blushed, instinctively leaning back some before clearing his throat. “You can ask all the questions you want after, but depending on how much I pour into this, it might not be until tomorrow.” Sans nodded in understanding.

Taking a deep breath, Harry dug out his wand and pointed it at the machine. Summoning a bit of magic, Harry intoned, ‘reparo’ making the slight wand movements. At Sans gasp, Harry turned to watch the skeletons expression as he watched some parts floated over to the machine and inserted themselves into spaces and others leaving the machine altogether.

When it was done, Sans was standing there with his jaw unhinged, eyes wider than Harry ever seen and an expression of disbelief on his face.

“what?”

Harry grinned a bit and patted the short guys shoulder. He didn't use all his energy, but it took more power than usual. Maybe because the machine was never fixed to work before.

“It should work now, but if it doesn't i can try again.” Harry offered with a tired smile. Sans shook his head. 

“no, i need to try it.” Sans shakily walked over and flipped a switch on the side of the machine, mechanical whirrs filled the room, and Harry watched as light flickered at the corners of the metal doorway. A few more switches later and the whole portal lit up. Finally, Sans pressed a button and closed his eyes. Harry quickly closed his, just in time to see a flask of white against his eyelids.

At the sound of a gasp, Harry opened his eyes and saw Sans staring up at… another skeleton?

“What-”

“Sans!”

Harry stared as the two skeletons stared at each other in wonder. Finally, Sans gave a mighty grin and spoke.

“hey g. looks like you a-void-ed aging well.”

Harry looked on in confusion as the new monster burst out laughing. 

“It Seams As Though You Still Haven't Got A New Jacket.”

Sans shrugged. “what can i say? i can't thread it.”

Harry groaned, collapsing into the chair.

“Oh, Hello. I Haven't Introduced Myself Yet. My Name Is W. D. Gaster.”

“I’m Harry,” Harry said holding his hand out. Gaster took it and Harry was shocked to feel a hole the size of a galleon where his palm should be. Sans must have seen his reaction because he chuckled a bit and patted Harry’s shoulder. 

“gaster is kinda like my and papyrus’ dad. we weren't born the way other monsters are, gaster made us. he used the bones in his palms to help create our bodies.”

“Oh!” Harry flushed, then scolded himself. Why was he getting so flustered suddenly. Gaster noticed Harry’s predicament and let out a belly deep chuckle. At Sans questioning look and Harry avoiding eye contact as much as he could, Gaster shook his head.

“uh, sorry to say, but paps forgot about you too. i don't know how much you saw from the void…”

Gaster grimaced. “I Saw Enough.”

“well, let’s get you upstairs. it's been long enough for papyrus to get undyne off our back.” Sans said, walking towards the door. Gaster and Harry followed the short skeleton out to a new world of possibilities.


End file.
